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Posted on Sun, Dec. 29, 2002 Animal-to-human transplants hold potential BY FELICE FREYER The Providence Journal SOUTH KINGSTOWN, R.I. - KRT NEWSFEATURES (KRT) - People who remember Baby Faye, who for four weeks in 1984 had a baboon heart beating in her tiny chest, may think that the practice of transplanting animal organs to humans is a doomed science, and a morally suspect one at that. But in fact, xenotransplantation - the transfer of animal cells, tissues or organs to humans - will soon be ready for medical practice and can help many people with diabetes, Parkinson's disease and other ailments, a University of Rhode Island professor said last month at the University of Rhode Island's colloquium on Genetic Technology and Public Policy. Richard C. Rhodes III, vice provost and professor of animal and veterinary science, said that failures of xenoplantation have been well publicized, while the successes have been quieter and harder to grasp. "Xenotransplantation holds tremendous potential," he said. Rhodes started his lecture, titled "From Animals to Humans: Progress, Prospects and Problems with Xenotransplantation," by projecting a cartoon of a creature genetically engineered from a human, a trout and a turnip. The scientist admiring the bizarre creation comments, "I'm not sure why we did it, but why the hell not?" The cartoon, Rhodes said, raises an important question for biotechnology: "Ought we to do what we can do?" Should we put baboon hearts in human babies? Should we raise pigs just to harvest their organs? One reason for even asking, Rhodes said, can be found in the statistics on organ donation: In 2001, 78,524 people were waiting for donated organs, but only 24,090 received them, and 6,238 died waiting for organs. Artificial organs have not worked well, and the quality of life of patients who have tried them has been very low. Raising awareness of organ donation has not yielded enough organs. Of course, the best-known experiments in animal-to-human transplants have fared no better. Doctors in the 1960s tried baboon and chimpanzee kidney transplants, but no patient lived more than 70 days. In 1993, transplant pioneer Dr. Thomas Starzl tranplanted baboon livers into two HIV patients, but they soon died. Meanwhile, though, outside the glare of publicity, other forms xenotransplantation have met with greater success, Rhodes said. Pig heart valves have long been used to replace failed valves in human hearts. In 1998, a patient's blood was successfully filtered through a pig's liver outside his body. Neural cells from pigs have been used experimentally to treat Parkinson's disease and Huntington's disease. Why pigs instead of primates? Although monkey and apes are closely related to humans, our fellow primates are not good sources of tissues for human use. They carry many viruses that people can catch, require complex and costly housing arrangements, take a long time to grow up, and have long pregnancies and low birth rates. Pigs are exactly the opposite, Rhodes said. They're easy to care for, have lived in close proximity to people for generations, and produce lots of young quickly. But there's a big problems with pigs. Pig cells, like those of all nonprimates, bear a marker that human immune system strongly recognizes as foreign. Pig organs implanted in a human trigger an extreme form of rejection that rapidly shuts down the blood vessels. Now, however, a possible solution is at hand. In September 2001, researcher Randy Prather of Immerge BioTherapeutics reported that he had genetically engineered pigs so that their cells do not bear the "foreign" marker. Theoretically, organs harvested from such pigs would not induce the extreme immune reaction. Xenotransplantation still poses other challenges, Rhodes cautioned, particularly the possibility of transmitting viruses from animals to humans that could then infect other humans. And questions of animal welfare must be addressed. Rhodes said he doesn't believe that animals have rights, but that humans have a moral obligation to treat them well. But these are issues that can be dealt with, he said. "Ought we to do what we can do?" Rhodes asked, returning to his original question. "I would say, `Yeah.' " The potential to help people suffering from diabetes, organ failure, Parkinson's disease, Huntington's disease, epilepsy and stroke is just too great to ignore, he said. But, Rhodes added, "Before we move forward, it's important that we implement cogent policies." He quoted Sir Roy Calne, the British transplant surgeon, as saying 10 years ago, "Clinical xenotransplantation is just around the corner, but unfortunately it may be a very long corner." "That corner," Rhodes said, "is very close and in fact may even be here now." --- SOURCE: The Providence Journal http://www.centredaily.com/mld/centredaily/news/4835258.htm * * * Murray Charters <[log in to unmask]> http://www.geocities.com/murraycharters/ ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn